More than 150 different drugs are being researched around the world. Most are existing drugs that are being trialled against the virus. The World Health Organisation (WHO) has launched the Solidarity trial aimed at assessing the most promising treatments. The UK says its Recovery trial is the the world’s biggest, with more than 5,000 patients already taking part and multiple research centres around the world are attempting to use survivors’ blood as a treatment
There are three broad approaches being investigated:
Antiviral drugs that directly affect the coronavirus’s ability to thrive inside the body
Drugs that can calm the immune system – patients become seriously ill when their immune system overreacts and starts causing collateral damage to the body
Antibodies, either from survivors’ blood or made in a lab, that can attack the virus
Dr Bruce Aylward, from the World Health Organisation, said Remdesivir is the only drug that showed any signs of effectiveness, after he visited China. The antiviral drug was originally designed to treat Ebola, but other options proved more effective. However, it has since been shown to be effective at treating other deadly coronaviruses such as the Middle East respiratory syndrome and severe acute respiratory syndrome, and also in animal studies, leading to hopes it will also be effective against the Covid-19 coronavirus.
Leaked results from trials led by the University of Chicago also suggested the drug was effective. It is one of the four drugs in the WHO Solidarity trial.
There has been much talk, but little evidence, that a pair of HIV drugs – lopinavir and ritonavir – would be effective at treating coronavirus. There has been some evidence they can work in the laboratory, but studies in people have been disappointing. The combination did not improve recovery, reduce deaths or lower levels of the virus in patients with serious Covid-19.
Another existing treatment being investigated is Malaria drugs, which are part of both the Solidarity and Recovery trials. Chloroquine, and a related derivative, hydroxychloroquine, may have antiviral and immune-calming properties.
The drugs have been thrust into the spotlight as potential coronavirus therapies, largely due to claims made by President Trump, but there is still scant evidence on their effectiveness.
Immunity drugs are another type being trialled. If the immune system overreacts to the virus then it can cause inflammation throughout the body. The Solidarity trial is investigating interferon beta, which is used to treat multiple sclerosis, and lowers inflammation. Interferons are a group of chemicals released by the body when under attack by a virus. The UK’s Recovery Trial is investigating dexamethasone – a type of steroid used to reduce inflammation.
And finally, survivor immunity is also an avenue worthy of exploring. People who survive an infection should have antibodies in their blood that can attack the virus. The US has already treated 500 patients with what’s known as “convalescent plasma”, and other countries are getting involved too.
Rolling out a cure
It is too soon to know when we might have a drug that can treat the coronavirus. However, we should start to get the results of trials in the next few months. This is much earlier than we will know if a vaccine (which protects against infection rather than treat it) is effective.
This is because doctors are testing drugs that have already been developed and are known to be safe enough to use, whereas vaccines researchers are starting from scratch.
Some completely new, experimental, coronavirus drugs are also being tested in the laboratory but are not yet ready for human tests.